Drum caster



July 31, 1956 Filed April 15, 1953 J.V.CARUSLE ETAL DRUM CASTER 4 Sheets-Sheet 1 FIG.L

JAMES v. CARLISLE By JOHN c. COPES CLARENCE L.WEEKS WOODROW F. ZACHARIAH ATTORNEY-911M y 1956 J. v. CARLISLE ETAL 2,756,472

DRUM CASTER Filed April 15, 1953 4 Sheets-Sheet 2 FIG.2.

IN VE N TORS.

JAMES v. CARLISLE By JOHN c. COPES CLARENCE L. WEEKS WOODROW F. ZACHARIAH ATTORNEYTW July 31, 1956 Filed April 15, 1953 FIG.5

J. V. CARLISLE ET AL DRUM CASTER 4 Sheets-Sheet 3 lNVENTORS.

JAMES v. CARLISLE y JOHN c. COPES CLARENCE WEEKS WOODROW F. ZACHARIAH Arrow/MW July 31, 1956 Filed April 15, 1953 J. V. CARLISLE ET AL DRUM CASTER FIG. 4.

4 Sheets-Sheet 4 IN VE N TORS.

JAMES v. CARLISLE y JOHN c. COPES CLARENCE L.WEEKS WOODROW F. ZACHARlAH ATTORNEY 79M United States Patent O DRUM CASTER James V. Carlisle, Baton Rouge, John C. Copes, Denham Springs, and Clarence L. Weeks and Woodrow F. Zachariah, Baton Rouge, La., assignors to Ethyl Corporation, New York, N. Y., a corporation of Delaware Application April 15, 1953, Serial N 348,939

5 Claims. (Cl. 2257.3)

This invention relates generally to a drum caster and more particularly, but not exclusively, to a drum caster for use in solidifying and flaking molten metals, such as sodium or sodium-lead alloys.

Drum casters or flakers have been used for a number of years for solidifying or flaking various materials. To a lesser extent, they have been used to flake sodium-lead alloys to provide them in a desirable physical form for reaction with ethyl chloride in the manufacture of tetraethyl lead. Such use and apparatus is disclosed in U. S. Patent No. 2,561,636.

Drum casters heretofore known are unsatisfactory for flaking molten metals. Due to the high melting point of metals, the drum caster must be operated at extremely high temperatures i. e. above about 400 C. for sodiumlead alloy. In addition, in the successful and efficient drum casting of metals, in contrast to other non-metallic compounds, the temperature of this system must be maintained within very close limits, and the position of the scraper blade must be located and maintained with extreme accuracy relative to the rotating drum. Otherwise, excessive wear and gouging of the drum caster parts results and the flaked product is of inferior quality. Moreover, slight variations in the level of the molten -material to be drum flaked in the molten reservoir or container results in operational difficulties and in the production of an undesirable flaked product. Thus, erratic operation of the unit and substantially increased maintenance and operation of cost result.

For the above reasons, no cemmercial use, at least in this country, has been made of a drum caster for solidifying sodium-lead alloys. Instead, flaked alloy has been produced by bed casting, i. e. solidifying the alloy in large sheets and thereafter breaking up the sheet in massive and elaborate vibratory conveyors. The investment cost of the latter apparatus is many times that of the drum caster of this invention, operational costs are higher, and maintenance costs are considerably higher. In addition, the drum casting apparatus of this invention requires only a fraction of the floor area necessary for the prior bed casters, based on an equal alloy production. Along with the above advantages, the drum caster disclosed and claimed herein produces a superior product.

It is accordingly an object of this invention to provide an improved drum caster. Another object of this invention is to provide a drum caster suitable for use in the flaking of metals, such as sodium or sodium-lead alloys, which provides a highly uniform flaked product and which can be operated continuously over long periods of time with trouble-free operation, a minimum of periodic adjustment, and low maintenance costs. Other objects of this invention will be apparent from the following description and appended claims, reference being made to the accompanying drawings forming a part of the specification wherein like reference characters designate corresponding parts in the several views.

In the drawings:

Figure l is a top plan view of a drum caster ematented July 31, 1956 a at bodying the features of the present invention, portions thereof being broken away for clarity.

Figure 2 is a front elevational view of the drum caster of Figure 1, having portions thereof broken away for clarity.

Figure 3 is a sectional view taken substantially on the line 3-3 of Figure 1.

Figure 4 is a sectional view taken substantially on the line 4-4 of Figure 1, and

Figure 5 is a fragmentary enlarged sectional view taken substantially on the line 5-5 of Figure 3.

The above and related objects are each obtained by the drum caster disclosed herein and shown in the accompanying drawings. This drum caster comprises several novel elements and features, each of which cooperate with one or more of the other novel elements in the accomplishment of these objects.

One novel feature of the present drum caster comprises solely supporting a scraper blade independently of the molten metal container, which scraper cooperates with the drum to remove or lift solidified metal flakes from the drum. This external, independent support of the scraper blade eliminates thermal variations in the position of the scraper blade relative to the drum, once the unit is adjusted. However, since the cutter portion of the scraper blade and the drum are still subjected to the same high temperatures as in prior drum casters, the efiicient operation thereof cannot be fully explained by the elimination of thermal variations. Accordingly, the success of this novel drum caster is not completely understood.

The drum caster of this invention has been operated with sodium-lead alloys above the melting temperature thereof over long periods of time without requiring adjustment. Moreover, upon inspection of the scraper blade and drum thereafter, there has been essentially no evidence of gouging or undue wear between the parts, and the product obtained from such operation has been highly uniform and of exceptional quality.

Another novel feature of this invention comprises the use of a liquid controller to maintain a constant level of the molten metal in contact with the drum. This device has proven surprisingly effective in maintaining a constant thickness of solidified metal on the drum and has intimately cooperated with the improved scraper blade mounting to provide trouble-free and efficient operation of the unit. While a wide variety of level controllers are suitable in certain cases, the inert gas device disclosed herein is highly effective for this purpose and is particularly sensitive to variations in the level of the molten material.

Another novel feature disclosed herein comprises the provision of a high-level safety mechanism which completely and automatically flushes the drum caster of molten metal in the event of a malfunctioning of the level control device. Thus, in the event of a leak of the inert gas used in the level control device or other abnormal operation, such as would cause an undue rise of the liquid level in the container, the safety mechanism will automatically flush the drum caster to prevent further and irreparable damage thereto and permit the necessary maintenance and repair of the unit without undue delay.

Other features which cooperate to provide the highly etficient operation obtainable with the drum caster of this invention include a means for adjusting the scraper blade axially of the drum to locate grooves therein with corresponding and cooperating grooves and lands in the drum. Also, this drum caster employs a novel discharge valve which cooperates with the automatic high level liquid safety mechanism to prevent the flowback of slag and other solid impurities to the molten metal 3 source, upon flushing of the device. Also, a means is provided to maintain a constant level of coolant in the drum, thus cooperating with the alloy level controller to maintain a constant solidification on the surface of the drum.

One modification of a drum caster embodying the features of this invention for flaking a molten metal is illustratedin the drawings and, with particular reference to Figures 2 and 4, comprises generally a liquid container 20, mounted on a main support 32; a cooled drum 40 supported externally of the container on the main support 32 and rotatable Within the container, the drum 40 being positioned so as to extend below the surface of the liquid 12 to be flaked and cooled to efiect solidification of the molten liquid on the outer surfaces thereof; a scraper blade 80 supported externally of the liquid container and contacting the periphery of the cooled drum at a suitable angle to scrape or lift the solidified film of material from the drum. The drum caster 10 disclosed herein also includes a molten liquid feed pump 110 to supply molten liquid to the container 20 from a suitable source; an automatic feed control mechanism 120 for the molten liquid; and a liquid level safety mechanism 160 responsive upon a defect in the automatic control mechanism 120 and adapted to automatically emPl the container 20 of molten liquid.

In general, .the liquid container 20 is shown as a sheet metal housing containing an inlet port 22 for the molten liquid and an outlet chute 24 (see Figure 3) for the flaked material. 7 ing floor portion 26 adapted to facilitate gravity flow of the molten metal to empty the oontainerof liquid interruption of operation of the unit. Heating units 28 are provided for maintaining an elevated temperature within the drum caster, shown in the drawings as a plurality of tubes positioned externally along the floor 26 and lower sides 30 of the container 20 adapted to receive electrical resistant heating units (not shown).

The molten liquid 12 is pumped to the container 20 through the inlet port 22 controlled by a valve 122. i The latter is positioned in the lowest section of the floor portion 26'of the container 20 and is con-trolled by, the valve stem 124. The valve seat 1 26 is constructed so as to screen large particles or slag from the molten liquid 12 upon a'flow-back of the liquid to the source, such as upon a. planned interruption of operation or upon automatic operation of the liquid level safety mechanism 160.

As shown, the valve seat includes an annular baflle plate 128 provided with a plurality of ports 130 positioned below the upper edge of the valve, opening. Thus, slag or'other solid impurity, which tends to float on the surface of the liquid, is retained in the container 20 and the flow from the container, at least at lower levels, is directed through the ports 130 in the baffle' plate 128 The valve 122 can be hydraulically, pneumatically or electrically operated. As shown in the drawings, the valve is pneumatically operated by compressed air, nitrogen or other suitable gas. The high pressure compressed gas flows through the line 132 from a source (not shown) and is controlled by a pressure unit 134. The high pressure gas enters the pneumatic cylinder 136 through the line 138, Operation of the pressure unit 134, to control a pneumatic cylinder 136, is responsive to the liquid level 12 in the container 20. Inert gas, i. e. nitrogen, having an incrementally higher pressure than the system pres sure in the container 20 enters through the line 140, and connects with liquid level bubbler tube 142 and the pressure unit 134. Nitrogen or other inert gas continuously passes downwardly through the bubbler tube l4 2 arid bubbtles up through the liquid 12;

Variations in the height of the liquid level. varies the pressure in the line to the pressure unit 134, varying the pressure differential between the lines 140 and 146. The latter line, connects with the, pressure unit 134. Line 146 also connects with the container 20 through line 144..

The container is also provided with a slop:

. can be maintained within the container 20.

7 When the liquid level rises above a predetermined height,

the differential pressure also rises, efiecting activation of the pneumatic cylinder 136 to open the valve 122. The liquid level 12 can be maintained by this control means at any convenient level. When drum casting a molten metal, such as sodium-lead alloy, the level is preferably maintained at approximately two (2) inches above the bottom of the drum 40 (see Figures 2 and 3).

The liquid container 20 is preferably air-tight when used for flaking flammable or easily oxidizable metals.

Typical examples of such molten metals are sodium, po-

, substituted by a thermally sensitive bulb, such as a thermometer, to reflect an unduly high liquid level in the container 20. Also, if desired, the thermally sensitive thermocouple can be substituted by a mechanical float control to inactivate the pump in the event of an excessively high liquid level within the container 2 0.

The liquid level safety mechanism 160, shown particularly in Figure 4' of the drawings, includes a thermally insulated cup 174 positioned below and surrounding a thermocouple 162 and supported from the top of the container 20 by a plurality of rods 176. The

cup is provided with an internal closed cavity filled with a a thermal insulation material 178. The thermocouple is surrounded (except at its lowermost end) by a tube 180 which is connected to a source of nitrogen or other inert gas (not shown) by the line 182. Gas passing downwardly through the tube 180 and thence into the gas space in the container 20 cools and maintains the thermocouple at a uniform temperature during normal operation of the drum caster 10. Also, the tube 180 is provided with a conically shaped deflector 184 positioned above the cup and adaptedto prevent hot liquid from splashing onto the thermocouple 162 during normal' operation'of thedrum caster. A baflle plate on the valve stem 124 also prevents splashingof hot liquid into the cup during flow of fresh, hot liquid into the container 20 through the valve 122. Thus, the thermally insulated cup 174, the inert gas tube 18.11, the deflector I84 and the baflle 125, all cooperate to maintain av constant and uniform temperature in the thermocouple during normal operation of the drum caster. However, in the event, of' an undue. rise in the liquid level within the container, such as will occur if a leak develops in the bubbler tube assembly 142,, hot liquid will overflowinto the cup 174 and contact the thermocouple 162:. The increase of temperature resulting. therefrom will activate the. potentiometer 168, which will in turn stop operation of the pump 110, The. pump is preferably of a centrifugal type which when, inactivated, will permit, aback flow'of liquid from the container 20. to a. liquid storage pot 112. Thus, when a high liquid level activates the liquid l'evelsafety mechanism 160, the vessel 20 is automatically emptied to permit inspection and. repair of the unit.

drum is a relatively thin-walled cylinder provided with a pair of trunnions 42 and 44 journalled' in bearings 46 and 48V respectively, (see Figures 1 and2). dfrumg40 is immersed, in the liquid 12; andis cooled a coolant 5.0 which circulates thereto from a refrigerator or. cooler (not shown). The coolant enters; the

drum 40 through. the per-foratedtube. 52. which. sprays the coolant onto the internal walls of the. drum. A

coolant return tube 54 is also provided having a downward extension 56 terminating at a predetermined distance above the bottom of the drum to maintain a uniform and constant level of coolant within the drum. This construction also aids in maintaining constant thermal operating conditions for the drum caster 10. If desired, nitrogen or other inert atmosphere can be supplied to the inside of the drum, through the line 58. An emergency overflow discharge 60 is also provided communicating with the drum 40. Packing 62 and 64 seal the trunnion with the container to prevent the escape of nitrogen or other inert atmosphere from the container or to prevent oxygen or air from entering the container. Packing 66 and 68 seals the end of the trunnion and prevents the loss of ntrogen from the inside of the drum 40.

As shown, particularly in Figure l, the drum and scraper blade 80 are adjustable relative to each other both axially of the drum and transverse thereto to assure efficient operation of the drum caster. tion, the scraper blade can be moved toward and away from the drum surface to vary the contact thereof with the drum surface. Preferably, for sodium-lead alloys, the angle between the blade and a perpendicular to the contacted drum surface is about 5. In addition, the drum 40 can be moved on the support 32 to move the drum axially relative to the blade 80. The scraper blade as well as the drum is mounted on the common support 32, externally of the container 20, so as to eliminate thermal and other variations which normally occur in the container Walls.

The trunnion 44 (Figure 2 of the drum is slidable axially within the bearing 48, the latter being secured to the support 32 by means of pedestal 49. The trunnion 42 (Figure l), on the other hand, is secured against axial movement relative to the bearing 46 and the latter is adjustably mounted on the support 32. The latter adjustment can best be seen with reference to Figure 1 wherein two pairs of opposed adjusting bolts 70 are threaded through brackets 72 provided by the base plate 74. The latter is secured to a pedestal (not shown) mounted on he support 32. The ends of the bolts bear against opposite sides of the base 47 of the bearing 46. Adjustment of the bolts 70 thus permits movement of the bearing 46 and axial movement of the drum 40 within the container 20 relative to the scraper blade 80. The bearing 46 is slidably mounted in suitable keyways on the base 74.

The drum 40 is provided internally with a plurality of abrading members 43 (Figure 2) for maintaining the internal surface of the drum free of scum or other residue which tends to reduce heat conductivity through the walls of the drum. These abrading members 43 can be bolts, metal scraps or similar articles which scrape against the internm walls during rotation of the drum.

The scraper blade 80 is adjustably mounted on a pedestal 82 secured to the support 32, as shown in Figure 2. The blade is secured to a rod 84, which, in turn, is adjustably secured against rotation at opposite ends within a pair of bushings 86 by the bolts 88 (only one pair shown). The bushings are adjustable relative to a base plate 90 to move the blade toward and away from the drum 40, the base plate being secured to the pedestal 82. Two pairs of opposed bolts 92 (Figure 1) for each bushing 86 are threaded in brackets 94 provided by the base plates 90 and the ends of the bolts engage opposite sides of the bushings 86. Corresponding movement of the bolts in the base plates 94 at opposite ends of the blade 80 will effect accurate and minute adjustment be tween the drum 40 and blade 80.

A pair of end scraper blades 100 (Figure 3) are provided at the ends of the drum 40 adapted to continuously remove the film of solidified material which accumulates on the ends of the drum. As shown, particularly in Figures 1 and 3, the end blade 100 is secured to and In this modifica- 5 supported by a rod 102 which extends through and journalled on the side wall of the container 20 and is operatively connected to an arm 104. The latter arm is provided with a pivotally supported forked connector 106 (Figure 2) which is rotatably secured to one end of an adjusting screw 108. The latter is threaded into' a bracket 109 secured to a wall of the container 20. R0- tation of the screw 108 effects longitudinal movement of the arm 104 and thus movement of the scraper blade to and away from the drum 40 to effect adjustment thereof.

The container 20 is provided at its top with a plurality of lights 21 and sight glasses 23 to permit visual inspection of the operation of the drum caster.

As shown in Figure 5, the drum 40 is provided with a plurality of spaced, peripheral, circumferential grooves 41 to aid in the suitable adherence of the solidified metal to the drum surface. Corresponding lands 81 are provided in the scraper 80 adapted to extend into the grooves to remove the solidified metal, the lands 81 having a width somewhat less than the grooves 41.

During startup operation of the drum caster 10, the various metallic parts thereof tend to expand with increases in temperature. The drum 40, as discussed above, is free to expand axially toward the right, as viewed in Figure 2, within the bushing 48. The scraper blade 80 is also keyed at the left and free to expand toward the right. Due to the difference of expansion of the blade 80 and the drum 40 and other thermal variations, the lands and grooves are frequently displaced during heating, the direction being completely unpredictable from one start-up to the next start-up of the drum caster. Accordingly, prior to start-up, it is desired to position the drum 40 relative to the scraper blade 80 so that the centermost grooves and lands are centered, permitting relative movement in either direction. After the temperature of the drum caster has attained steady state conditions, the drum 40 is then adjusted to place the lands essentially centrally Within the grooves 41, using the center grooves and lands as a gauge.

The operation of the drum caster illustrated in the drawings is as follows: Molten sodium-lead alloy 12 or other molten metal is fed to the container 10 from the supply vessel 112 by the pump through the valve 122 (see Figure 4). The latter valve controls the quantity and rate of alloy fed in response to the liquid level control 142. The drum 40 (Figure 3) continuously rotates within the container 10 at an angular speed of between about 318 R. P. M. Coolant, i. e. oil, is continuously circulated into and out of the drum (Figure 2) through the lines 52 and 54 respectively to cool the surfaces of the drum and to effect solidification of the molten metal thereon. When drum flaking sodium-lead alloy, the rate of flow of coolant is controlled to form a solidified layer of metal having a thickness of between about /z to inch, preferably about ,4 inch. As is apparent, the rate of rotation of the drum and the depth of immersion of the drum in the molten liquid also determines the thickness of the film or flake for each specific material to be drum flaked.

The solidified material is removed from the drum 40 by the scraper blade 80 (Figure 3) and empties into the hopper 24. When drum flaking sodium-lead alloy, a hopper booth (not shown) is connected to the hopper 24 and the entire system can be maintained under an inert atmosphere, i. e. nitrogen. Preferably, a small clearance is provided between the lands and grooves of the drum 40 and scraper blade 80, generally not greater than about 0.050 inch and preferably about 0.030 inch.

In operation, the container 40 is maintained under a slight inert atmosphere, about 1 inch of water pressure. A higher inert gas pressure is employed in the liquid level control mechanism 142, varying during operation but having a maximum pressure of about 30 inches of Water.

The operating difierential pressure, however, can, be varied widely' without deviating from this. invention. However, the liquid level should be maintained relatively constant, for. efficient trouble-free operation. The actual depth of immersion. of the drum, if maintained constant during operation, can be between about 1 and 6 inches, with a preferred depth of about 2 inches.

. We claim:

l-. A drum caster adapted. to solidify and flake a hot molten metal; comprising. a closed container for the molten metal, means to supply an inert gas atmosphere within said container, a support means positioned externally and independently of said container and spaced therefrom to prevent appreciable heating thereof fromthe hot moltenmetal in said. container, a cooled drum mounted for rotation in said container and adapted to.

be partially immersed in the hot molten metal, said drum having trunnions extending through. the walls of said container and yieldably sealed therewith, a knife means operatively positioned with respect to said drum to remove the solidiiied metal therefrom and having a supporting portion extending through and yieldably sealed with the walls of said container,- said trunnions. of said drum being journal'ed on said support means for rotating about a fixed axis and said supporting. portion of said knife means being secured to saidsupport means to prevent relative vertical movement of said drum and knife upon variation in the temperature and expansion of the walls of said container, control means to maintain a constant. level of molten metal in said container, and means to maintain a constant quantity of coolant in said drum.

2. A drum caster in accordance with claim 1 wherein said drum and knife means are provided with matching grooves and lands, and means are provided for adjustment of said drum in an axial direction and for adjustment of said knife means in a direction transverse to the axis of said drum to permit accurate positioning of the corresponding grooves and lands while the hot molten metal iswithin said container.

3. A drum caster adapted to solidify and flake a. hot molten. metal, comprising a closed container for the molten metal, means to supply an inert gas atmosphere within said container, a support means positioned externally of said container and spaced therefrom to prevent appreciable heating thereof from the hot molten metal in" saidcontainer, a cooled drum.mounted for rotation in said container and adapted to belpartially immersed in the hot molten metal, said drumhaving trunnions extending through the walls of said container and yieldably sealed therewith, a knife means operatively positioned with respect to said drum to remove the solidified metal therefrom and having a supportingportion extending through andyieldably sealedwith the walls of said container, said trunnions of said drum being journaled on said support means and said supporting portion of said knife means being secured" to said support means to prevent relative vertical movement of said" drum and knife upon variation in the temperature and expansion of the Walls of said container, control means to maintain a constant level of moiten metal in said' container, and means to maintain a constant quantity of coolant in said drum, said container being provided with a molten metal inlet port positioned near the bottom thereof and below the operating level of the molten metal therein, a source of molten metal positioned below said container, means to feed said molten. metal. to said. container; through said: inlet; port including a centrifugal. pump', aliquidlevel safety mechanism positioned; abovethe-normal level of the moltenmetal' and adaptedto con tact the molten metal upon raising of its level. beyond: its normal: height to automatically inactivate said centrifugal pump and. to permit the molten metal in said container to return. by gravity flow tosaid molten metal source.

4. A drum caster inaccordance with claim 3 whereinsaid inlet port is provided with a. valve and, valve seat, said valve seat comprising an annular baffle plate having its upper edge forming ,a valve opening, said plate hav-- ing a. plurality of relatively small ports therein positioned below the upper edge thereof communicating with said molten metalsource, the ports in said baflle plate permitting the return of molten metal to said source upon operation of said liquid level safety mechanism but preventing the return of solid impurities thereto.

5. A drum caster adapted to-solidify and flake a hot molten metal, comprising a closed container for the molten metal, means to supply an inert gas atmosphere withinsaid container, a support means positioned exterr nally of said container and spaced therefrom to prevent appreciable heating thereof from the hot molten metal in said container, a cooled drum mounted for rotation in said container and. adapted to be partially immersed inthe hotmolten metal, said drumhaving trunnions extending through. the walls of said container and yieldably sealed. therewith, a knife means operatively positioned with respect to said drum to remove the solidified metal therefrom and having a supporting portion extending. through and yieldably sealed with the walls of said container, said trunnions of saiddrum being journaled on said A support. means and said supporting portion of said knife means being secured to said support means to prevent relative vertical movement of said drum and knife upon variation in the temperature and expansion of the walls.

of said container, control means to maintain a constant level of molten metal in said container, and means to maintain a constant quantity of coolant in said drum,

said control means having a bubbler tube having an open endpositioned below the level of the molten metal in said container, a source of gas at a pressure above the gas pressure in said container and connected to said bubbler tube to maintain a continuous flow of gas through said tube and out of said end positioned below the molten metal level, and meansresponsive to variations in the pressure of the gas in said tube to control the flow of molten metal to-said container.

References Cited in the file. of this patent UNITED STATES PATENTS 1,220,211: Feldkamp et al Mar. 27, 1917 1,879,336 Foley et al Sept. 27, 1932 1,936,332 Lindenberger Nov. 21, 1933 2,074,812 Sendzimir Mar. 23 1937 2,468,704 Pippin Apr, 26, 1949 2,555,134 Hunter May 29, 1951 2,561,636 Pyk July 24', 1951. 2,660;769 Bennett Dec. 1', 1953 2,682,691 Harter July 6, 1954 FOREIGN PATENTS 686,033 Great Britain Jan. 14, 1953 (Corresponding U. S. 2,682,691 July 6, 1954;) 

1. A DRUM CASTER ADAPTED TO SOLIDIFY AND FLAKE A HOT MOLTEN METAL, COMPRISING A CLOSED CONTAINER FOR THE MOLTEN METAL, MEANS TO SUPPLY AN INERT GAS ATMOSPHERE WITHIN SAID CONTAINER, A SUPPORT MEANS POSITION EXTERNALLY AND INDEPENDENTLY OF SAID CONTAINER AND SPACED THEREFROM TO PREVENT APPRECIABLE HEATING THEREOF FROM THE HOT MOLTEN METAL IN SAID CONTAINER, A COOLED DRUM MOUNTED FOR ROTATION IN SAID CONTAINER AND ADAPTED TO BE PARTIALLY IMMERSED IN THE HOT MOLTEN METAL, SAID DRUM HAVING TRUNNIONS EXTENDING THROUGH THE WALLS OF SAID CONTAINER AND YIELDABLY SEALED THEREWITH, A KNIFE MEANS OPERATIVELY POSITIONED WITH RESPECT TO SAID DRUM TO REMOVE THE SOLIDIFIED METAL THEREFROM AND HAVING A SUPPORTING PORTION EXTENDING THROUGH AND YIELDABLY SEALED WITH THE WALLS OF SAID CONTAINER, SAID TRUNNIONS OF SAID DRUM BEING JOURNALED ON SAID SUPPORT MEANS FOR ROTATING ABOUT A FIXED AXIS AND SAID SUPPORTING PORTION OF SAID KNIFE MEANS BEING SECURED TO SAID SUPPORT MEANS TO PREVENT RELATIVE VERTICAL MOVEMENT OF SAID DRUM AND KNIFE UPON VARIATION IN THE TEMPERATURE AND EXPANSION OF THE WALLS OF SAID CONTAINER, CONTROL MEANS TO MAINTAIN A CONSTANT LEVEL OF MOLTEN METAL IN SAID CONTAINER, AND MEANS TO MAINTAIN A CONSTANT QUANTITY OF COOLANT IN SAID DRUM. 